docs/scheduler/sched-bwc: formatting fix

Since commit d6a3b247 these three lines are merged into one by the
RST processor, making it hard to read. Use bullet points to separate
the entries, like it's done in other similar places.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-2-kolyshkin@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>